ABC/Randy HolmesGet ready to step into Mariah’s World. Mariah Carey’s new docu-series premieres on E! Sunday. In a new sneak peek, the singer talks about coming from nothing before hitting it big.

She opens up while sailing on a yacht with her nephew Shawn. “I think me and Shawn have a great relationship because we both understand what it’s like to literally come from nothing,” she says. “We did not grow up this way, people have to understand this.”

Mariah explains that her mother encouraged to sing at around four years old and she started doing demos when she 12. “I moved to Manhattan alone as a teenage girl,” she says. “It was an exciting time for me, even though I had nothing.”

She adds, “I lived, like, on a mattress on the floor. I was writing my songs and being a horrible waitress. My demo tape ended up at Sony and they signed it away.”

In another preview clip, she works on her tour set list with musical director Big Jim Wright.